54 research outputs found

    Scattering Suppression from Arbitrary Objects in Spatially-Dispersive Layered Metamaterials

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    Concealing objects by making them invisible to an external electromagnetic probe is coined by the term cloaking. Cloaking devices, having numerous potential applications, are still face challenges in realization, especially in the visible spectral range. In particular, inherent losses and extreme parameters of metamaterials required for the cloak implementation are the limiting factors. Here, we numerically demonstrate nearly perfect suppression of scattering from arbitrary shaped objects in spatially dispersive metamaterial acting as an alignment-free concealing cover. We consider a realization of a metamaterial as a metal-dielectric multilayer and demonstrate suppression of scattering from an arbitrary object in forward and backward directions with perfectly preserved wavefronts and less than 10% absolute intensity change, despite spatial dispersion effects present in the composite metamaterial. Beyond the usual scattering suppression applications, the proposed configuration may serve as a simple realisation of scattering-free detectors and sensors

    Assembling nanostructures from DNA using a composite nanotweezers with a shape memory effect

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    The article demonstrates a technique for fabricating a structure with the inclusion of suspended DNA threads and manipulating them using composite nanotweezers with shape memory effect. This technique could be suitable for stretching of nanothin DNA-like conductive threads and for measuring their electrical conductivity, including the I-V characteristic directly in the electron microscope chamber, where the nanotweezers provide a two-sided clamping of the DNA tip, giving a stable nanocontact to the DNA bundle. Such contact, as a part of 1D nanostructure, is more reliable during manipulations with nanothreads than traditional measurements when a nanothread is touched by a thin needle, for example, in a scanning tunnel microscope.Comment: To be presented on IEEE 3M-NANO 201

    Comparative Analysis of Mycoplasma gallisepticum vlhA Promoters

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    Mycoplasma gallisepticum is an intracellular parasite affecting respiratory tract of poultry that belongs to class Mollicutes. M. gallisepticum features numerous variable lipoprotein hemagglutinin genes (vlhA) that play a role in immune escape. The vlhA promoters have a set of distinct properties in comparison to promoters of the other genes. The vlhA promoters carry a variable GAA repeats region at approximately 40 nts upstream of transcription start site. The promoters have been considered active only in the presence of exactly 12 GAA repeats. The mechanisms of vlhA expression regulation and GAA number variation are not described. Here we tried to understand these mechanisms using different computational methods. We conducted a comparative analysis among several M. gallisepticum strains. Nucleotide sequences analysis showed the presence of highly conserved regions flanking repeated trinucleotides that are not linked to GAA number variation. VlhA genes with 12 GAA repeats and their orthologs in 12 M. gallisepticum strains are more conserved than other vlhA genes and have narrower GAA number distribution. We conducted comparative analysis of physicochemical profiles of M. gallisepticum vlhA and sigma-70 promoters. Stress-induced duplex destabilization (SIDD) profiles showed that sigma-70 group is characterized by the common to prokaryotic promoters sharp maxima while vlhA promoters are hardly destabilized with the region between GAA repeats and transcription start site having zero opening probability. Electrostatic potential profiles of vlhA promoters indicate the presence of the distinct patterns that appear to govern initial stages of specific DNA-protein recognition. Open state dynamics profiles of vlhA demonstrate the pattern that might facilitate transcription bubble formation. Obtained data could be the basis for experimental identification of mechanisms of phase variation in M. gallisepticum

    Dysfunction in Ribosomal Gene Expression in the Hypothalamus and Hippocampus following Chronic Social Defeat Stress in Male Mice as Revealed by RNA-Seq

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    Chronic social defeat stress leads to the development of anxiety-and depression-like states in male mice and is accompanied by numerous molecular changes in brain. The influence of 21-day period of social stress on ribosomal gene expression in five brain regions was studied using the RNA-Seq database. Most Rps, Rpl, Mprs, and Mprl genes were upregulated in the hypothalamus and downregulated in the hippocampus, which may indicate ribosomal dysfunction following chronic social defeat stress. There were no differentially expressed ribosomal genes in the ventral tegmental area, midbrain raphe nuclei, or striatum. This approach may be used to identify a pharmacological treatment of ribosome biogenesis abnormalities in the brain of patients with "ribosomopathies.&quot

    A Dose Finding Study of Weekly and Every-3-Week nab-Paclitaxel Followed by Carboplatin as First-Line Therapy in Patients with Advanced Non-small Cell Lung Cancer

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    INTRODUCTION: This nonrandomized study aimed to identify the optimal dose of every-3-week (q3w) and weekly nab-paclitaxel plus q3w carboplatin as first-line therapy in patients with advanced non-small cell lung cancer (NSCLC) for a phase 3 trial. METHODS: Previously untreated patients with advanced NSCLC enrolled sequentially into seven cohorts (25 patients/cohort, N = 175). Cohorts 1 to 4 and 5 to 7 received nab-paclitaxel q3w and weekly, respectively. Patients were evaluated for efficacy and safety. RESULTS: The most common treatment-related > or = grade 3 adverse events were neutropenia (60%), neuropathy (19%), fatigue (9%), and thrombocytopenia (29%) (no grade 4 neuropathy or fatigue). A 100 mg/m(2) weekly nab-paclitaxel produced less serious adverse events than other doses/schedules. Response rate (RR) was greater in the weekly versus q3w cohorts (47% vs. 30%). Median progression-free survival (PFS) ranged from 4.8 to 6.9 months, and overall survival (OS) ranged from 8.3 to 15.0 months (all cohorts). Patients receiving 100 mg/m(2) weekly nab-paclitaxel achieved 48% RR with 6.2 and 11.3 months of PFS and OS, respectively. In a retrospective analysis, patients with nonsquamous cell carcinoma receiving weekly nab-paclitaxel had significantly improved RR (59.4% vs. 23.5%, respectively, p = 0.003), and >2 months longer PFS and OS compared with q3w schedule. In patients with squamous cell carcinoma, the q3w schedule significantly increased PFS by 3 months (p = 0.014) and OS by >2 months (no difference in RR) compared with the weekly schedule. CONCLUSION: nab-Paclitaxel plus carboplatin is an effective therapy for advanced NSCLC. Based on favorable efficacy and safety profiles, a phase 3, randomized, multicenter study comparing 100 mg/m(2) weekly nab-paclitaxel plus q3w carboplatin to solvent-based paclitaxel plus carboplatin has enrolled patients

    Design, Performance, and Calibration of CMS Hadron Endcap Calorimeters

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    Detailed measurements have been made with the CMS hadron calorimeter endcaps (HE) in response to beams of muons, electrons, and pions. Readout of HE with custom electronics and hybrid photodiodes (HPDs) shows no change of performance compared to readout with commercial electronics and photomultipliers. When combined with lead-tungstenate crystals, an energy resolution of 8\% is achieved with 300 GeV/c pions. A laser calibration system is used to set the timing and monitor operation of the complete electronics chain. Data taken with radioactive sources in comparison with test beam pions provides an absolute initial calibration of HE to approximately 4\% to 5\%

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

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    Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise. © 2015
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